In a Parisian nightclub, Diane Churchill, an American woman, and her father are fascinated to learn that Jacques Duryea, the young man seated at a table near them, is an international lover known as Toto, able to have any woman he wants. Toto finds Diane very attractive and manages to dance with her, but as soon as their dance is over, Diane, who disapproves of him, leaves with her father. In the following days, Toto follows Diane everywhere. After she accidentally shuts the car door on his hand, she takes pity on him and bandages his injury. At tea, Toto tells her that she is his ideal woman and now that he has found her, he is finished philandering. She wants to believe him, but while she visits him at home, Tania, a former mistress, arrives with several suitcases, clearly intending to live there. Diane leaves and when Toto returns, he forces Tania to leave. That night, Churchill attends a concert, leaving Diane home alone. Wearing a disguise, Toto sneaks into her house to beg forgiveness. She admits that she is in love with him. When Toto tells Churchill that he intends to marry Diane, Churchill agrees on the condition that Toto stay away from Diane for six months. He also demands that Toto see his doctor to insure that he is in good health. After an examination, the doctor warns Toto that he has a bad heart and the least excitement may cause it to burst. In order to stay alive, he must stop drinking and give up women entirely. When they hear the news, several of Toto's old girl friends want to nurse him. Toto tries desperately to get rid of them and an angry husband appears, intending to kill him. After all this excitement, the doctor warns that even one kiss will kill him. Then Diane tells Toto that her father is taking her back to America and offers to spend an hour with him that night. Not wanting to say no, Toto arranges for his funeral. Diane arrives right on time, and Toto kisses her, expecting to die immediately. Nothing happens, however, and it turns out that Churchill paid the doctor to lie in order to discover if Toto loved Diane more than life. Now that he really believes in Toto's love for his daughter, he allows them to marry.